Page 212 - Encyclopedia of Aquarium and Pond Fish, 3rd Edition

210 MARINE FISH: SETTING UP THE TANK

Heating and filtration

Tropical marine fish thrive at water temperatures of between 77°F (25°C)
and 81°F (27°C). Their natural reef environment changes little from day
to day, so they are poorly adapted to fluctuations in temperature and water
quality. As a result, reef fish are far less tolerant of change than their
freshwater cousins: creating and maintaining a constant environment
is the key challenge when keeping such species in a home aquarium.

Unless you live in a particularly
warm climate, you will need a heater
to maintain the water temperature in
your tank. Standard heaters contain Currents created on the
surface of the marine
a glass-encased heating element and aquarium (above) by
have an integral thermostat, which a power filter outlet
switches the unit on and off to replicate the motion of
waves over a reef (left),
maintain a preset temperature. These which helps to keep the
heating units are available in a range water well oxygenated.
of sizes and power ratings (wattages).
You should allow a rating of about 1
1
watt per ⁄4 gal (1 liter) of water,
1
or up to 2 watts per ⁄4 gallon
(1 liter) if the ambient temperature is particularly low. Heater safety
Many aquarists prefer to use two slightly underpowered The heater should be installed after all the rockwork and
heaters to keep the water at the desired temperature, rather tank decor are in place—this will minimize the risk
than a single, more powerful unit. The principle is that if one of accidental damage to its outer glass casing. It is also
heater fails, the other will be able to keep the temperature at a good idea to fit a heater guard—a ventilated shield
a reasonable level; and conversely, if one unit fails to switch around the heater—to prevent any direct contact
off, it will be insufficiently powerful to overheat the tank. between fish and the body of the heater, which can cause
serious burns. Never switch on the power until the
heater is completely submerged, and always turn off the
power before placing your hand in the water.
HEAT DISTRIBUTION A few species, notably boxfish (see pp.250–251),

The heater should be fixed where water can flow readily around it have extremely sharp teeth and will bite through
and so distribute warmed water around the tank; avoid parts of the the plastic casing of electrical cables that carry power
tank cluttered by rockwork and other fixtures. The sensible aquarist to the heater. For these fish, it is safer to use
is always skeptical about undergravel heating units (see p.33).
thermostat settings on heater
units—even the best units
can become unreliable, or fail Types of filtration
completely, with disastrous Filtration is needed to rid the tank of toxic wastes,
consequences. To guard against undesirable particles, and other dissolved chemicals.
this, fit the tank with a separate There are many different designs of filters, and their
thermometer (see p.33), and mode of action may be biological, mechanical, or
check the temperature regularly.
chemical, or a combination of these.
The heater unit is held in place with Biological filters remove nitrite and ammonia
suction caps. A small light on the unit
shows when it is operating. from the water (see p.34 for a full description of the
nitrogen cycle). They work by providing a home

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